Adoption of the Toxicity Criteria Rule does not automatically change previously approved or selected remedies. Changes in toxicity criteria used for remedial decisions are normally considered if a Five-Year Review is conducted for the site; this is further discussed in Question12 below. For previously closed (e.g., certified) sites that are not subject to a Five-Year Review, DTSC may re-examine a closed site if there is evidence or substantial concern that the decision is not protective. Remedial action may be warranted should the evaluation determine the original decision is inadequately protective of human health and the environment. This is consistent with applicable hazardous substance and waste laws and guidance and the requirement that DTSC use the best available science in its risk assessments. If a site is re-opened to ensure the remedy protects public health and the environment, then additional analysis or remedial work may be needed, depending on site-specific factors and the revised remedial goals that apply. However, the Toxicity Criteria Rule itself does not require reopening of a final remedial decision as the rule does not apply more stringent standards than DTSC’s past practice for developing screening levels and remediation goals.